The objectives of this proposal are to determine which cellular components regulate the motility and behavior of cultured normal cells and their transformed derivatives. Emphasis is placed on the function of the major components of the system of cytoplasmic fibers present in the majority of mammalian cell types including microfilaments, 10nm filaments and microtubules. These cytoplasmic fibers are thought to be responsible for controlling many aspects of behavior including cell attachment, spreading, surface topology, shape formation, locomotion, division and contact inhibition. The long term goal of these studies is to gain new insight into the mechanisms involved in the cellular basis of transformation to the neoplastic state which ultimately results in malignant tumor formation and metastasis. Experimental approaches involved in relating structure and function in this proposal include microscopical, physiological, immunological and biochemical techniques.